[0001] The present invention relates generally to improvements in a verifying device for
a key card which is used, for instance, as an electronic lock for entrance administration
or in a membership system.
[0002] Various methods have been proposed for a magnetic card verifying device and the present
inventor has previously proposed an influential method or system (disclosed in examined
Japanese Utility Model application documents Nos. 40781/75 and 38738/76 which have
been laid open to public inspection). The above previously proposed system is summarized
as follows. A magnetic card on which a reference magnetic signal . (hereinafter referred
to as a key code) having a large number of combinations was recorded is inserted into
a verifying device in advance as a set card. When another magnetic card on which a
magnetic signal or key code to be verified was recorded is inserted into the verifying
device as a key card, the key codes respectively recorded on the set card and key
card are compared and verified in the verifying device. When the key codes are coincident,
the verifying device generates an output indicative thereof.
[0003] Fig. 1 is a schematic diagram showing an example of a magnetic sensor used in such
a verifying device. In Fig. 1, reference numeral 1 designates an I-shape saturable
magnetic core, 2 a primary winding which is wound around the magnetic core 1, 3 a
secondary winding which is wound around the magnetic core 1 in the same way as in
the primary winding 2, 4 a high frequency (approximately 500 kHz) oscillator connected
to the primary winding 2, 5 and 6 magnetic signal (key code) recorded sections (magnet
or magnetized sections) of a set card and a key card, respectively. Reference letter
V designates the voltage which is induced across the secondary winding 3. The saturable
core 1 and the primary and secondary windings 2 and 3 constitute a saturable transformer
S.
[0004] Fig. 2 is a graph showing the input to output characteristic of such a saturable
transformer type magnetic sensor as mentioned above. When the magnetic field H applied
to the saturable core 1 increases in its absolute value to a value larger than the
saturation magnetic field Hs of the core 1, the saturable magnetic core 1 is saturated
as shown in Fig. 2. As a result, the output voltage V induced in the secondary winding
3 rapidly decreases at the saturation points as shown in Fig. 2. Accordingly, in the
case where the key code recorded section 6 is not loaded in the magnetic sensor, if
the magnetic field A generated by the set card with the key code recorded section
5 is larger than the saturation magnetic field +Hs as shown in Fig. 2, the output
voltage V from the magnetic sensor becomes small or substantially zero and the magnetic
sensor is therefore turned off. In this state, when the key card is inserted into
the magnetic sensor or verifying device, the magnetic field of the key f code recorded
section 6 of the key card is applied to the saturable core 1. In this case, if the
magnetic field generated by the key code recorded section 6 of the key card is oriented
in the direction indicated by letter B, which is opposite to the direction of but
of substantially the same magnitude as the magnetic field A (as shown in Fig. 2) the
magnetic field B cancels the magnetic field A so that the magnetic field applied to
the core 1 becomes substantially zero whereby a predetermined output voltage V
o is induced in the secondary winding 3. Thus the magnetic sensor is turned on to produce
an output indicating that the cards are coincident. If the magnetic field of the key
code recorded section 6 is in the direction as indicated at B' in Fig. 2 as may be
the case when the cards are not coincident, the magnetic fields A and B' together
are much larger +Hs so that the magnetic field applied to the core 1 in the magnetic
sensor remains in its off-state. Hence, no output is delivered therefrom. Moreover,
when the key card has no key code recorded section 6 (no magnet or is not magnetized),
as alternatively may be the case when the cards are not coincident, namely, when the
magnetic field by the section 6 is at point B° in the graph of Fig. 2, only the magnetic
field A is applied to the saturable core 1 so that the magnetic sensor is also held
in the off-state and hence no output is delivered therefrom. Accordingly, when an
output voltage V from the saturable transformer S is present, this indicates that
the key code recorded sections 5 and 6 on the set card and key card have been compared
and the key card has been verified. When a plurality (for example, 6 to 8) of magnetic
signals or key codes are to be verified, a plurality of key code recorded sections
and a plurality of saturable transformers corresponding to the former are utilized
as the verifying elements.
[0005] Fig. 3 is a schematic diagram showing a constructional example in which a plurality
of key codes are verified simultaneously according to the prior art system. In Fig.
3, parts corresponding to those of Fig. 1 are marked with the same references. Reference
numeral 5' designates a set card and 6' a key card. In this case, reference numeral
5 designates not the magnet but a magnetic signal or key code recorded point which
is magnetized on the set card 5' and reference numeral 6 designates a magnetic signal
or key code recorded point which is magnetized on the key card 6'. Each of the saturable
transformers S is the same as that in Fig. 1 and is shown more clearly from the electrical
point of view. The set card 5' with a plurality of key code recorded points 5 and
the key card 6' with a plurality of key code recorded points 6 are located on either
side of a plurality of saturable transformers S such that the magnetic fields generated
from the opposing key code recorded points 5 and 6 pass through the corresponding
saturable transformer S. Reference numeral 7 designates an amplifier and 8 verified
output terminal. When each of the saturable transformers S is connected in chain or
cascade as shown in Fig. 3, if any one of the saturable transformers S is turned off,
the output as a whole decreases and hence all of the saturable transformers S are
turned off. In other words, unless all of the saturable transformers S are turned
on, no output appears at the verified output terminal 8. Thus, the whole of a plurality
of key code recorded points can be verified at the same time.
[0006] A verifying device for a key card of the type shown in Fig. 3 is disclosed in US-A-3
780 268 (Rogers). The device comprises:
a set card on which a predetermined reference magnetic signal is recorded;
a first magnetic sensor comprising a first saturable core and a winding wound thereon;
an oscillator for supplying a voltage to said winding;
a switching element connected to said winding;
a power source connected to said switching element; and
an output terminal connected to said switching element for connection to an actuator.
[0007] The device disclosed in this patent provides an enabling output to the actuator when
the magnetic signal on the key card opposes that on the set card such that the saturable
core is not saturated.
[0008] This prior art system described above has the advantages that the key codes recorded
on the magnetic cards as many dots can be compared and verified with one other by
a simple circuit construction having only a few electronic parts and that a stable
DC output is generated only when the key code signals recorded on the key card 6'
are coincident with those on the set card 5'. However, this prior art system is not
free from the possibility that when a large current flows near the verifying device,
for instance by construction work or intentionally, or in the case of lightning, without
inserting the key card into the verifying device, the saturable transformer S thereof
is instantly turned on by an electromagnetic or electrostatic induction voltage caused
thereby and hence an output is generated therefrom. The first reason therefor is that,
since the output voltage from the saturable transformers S connected in cascade as
shown in Fig. 3 is small, approximately 0.2 Vpp, and this output voltage is amplified
and rectified to provide the verified-coincident output, the verifying device is apt
to be disturbed.
[0009] The second reason is that the saturable transformer S in each magnetic sensor of
the verifying device is arranged in such a manner that it is turned off normally or
when the key card is not verified (the cards are coincident) while it is turned on
when the key card is verified (the cards are coincident). As a result, when the saturable
transformer S is turned off and the disturbing voltage is applied to the small output
voltage generated from the saturable transformer S, the output voltage becomes large
and the saturable transformer S is turned on.
[0010] In practice, it is quite rare that the verifying device is disturbed so that it malfunctions.
However, if the verifying device is utilized for a door- locking system, even such
a small possibility of disturbance is not negligible. Therefore, it is necessary to
prevent the verifying device from being disturbed to malfunction.
[0011] Accordingly it is an object of the present invention to provide an improved magnetic
card verifying device.
[0012] It is another object of the present invention to provide a magnetic card verifying
device which is free from the defect inherent in the devices of the prior art.
[0013] It is still another object of the present invention to provide a magnetic card verifying
device which is resistant to disturbing voltages:
[0014] It is a further object of the present invention to provide a magnetic card verifying
device which is safe against a magnetic card made of strongly magnetized magnetic
material.
[0015] It is a stijl further object of the present invention to provide a magnetic card
verifying device which is particularly suitable for use with an electronic lock.
[0016] According to one aspect of the present invention, there is provided a magnetic verifying
device for a key card of the type disclosed in US-A 3 780 268 referred to above.
[0017] The device of the present invention is characterised in that:
the saturation magnetic field of said first satur- abJe core is larger in absolute
value than the magnetic field generated by the reference magnetic signal recorded
on said set card but is smaller in absolute value than the sum of the magnetic field
generated by the reference signal recorded on said set card and the magnetic field
generated by the key card magnetic signal when said key card is a correct card, so
that when a correct key card to be verified is inserted into the device with said
set card, the sum of the magnetic fields from said set card and said key card is larger
in absolute value than the saturation magnetic field of said first saturable core,
so that said saturable core is saturated, no output appears at said winding, said
switching element is turned off and an output indicating that said key card is coincident
with said set card is produced at the output terminal.
[0018] Other objects, features and advantages of the present invention will become apparent
from the following description taken in conjunction with accompanying drawings through
which the like references designate the same elements and parts.
[0019] In the drawings:
Fig. 1 is a schematic diagram showing an example of a magnetic sensor used in a previously
proposed magnetic card verifying device;
Fig. 2 is a graph showing the input to output characteristic of a saturable transformer
used in the magnetic sensor shown in Fig. 1;
Fig. 3 is a schematic diagram showing another example of a previously proposed magnetic
card verifying device by which the coincidence among a plurality of magnetic signals
or key codes is verified;
Fig. 4 is a graph showing the input to output characteristic of a saturable core used
to explain the principles of the invention;
Fig. 5 is a connection diagram showing an embodiment of the magnetic card verifying
device according to the present invention; and
Fig. 6 is a schematic diagram showing another embodiment of the magnetic card verifying
device according to the present invention.
[0020] The present invention is hereinafter described with reference to the attached drawings.
[0021] A first embodiment of the magnetic card verifying device according to the present
invention which is prevented from being misoperated by an electromagnetic or electrostatic
induction voltage will first be described. This first embodiment of the magnetic card
verifying device according to the present invention employs a saturable core for the
magnetic sensor of the verifying device in the same way as in the prior art system.
This embodiment of the magnetic card verifying device, however, is characterised by
the con- _ struction of its magnetic sensor which is operated as below. Contrary to
that of the prior art, the magnetic sensor used in this embodiment of the invention
is turned on when verification is not made, for instance when the key card 6' is not
coincident with the set card 5' (including the case where both the magnetic signals
recorded on the set and key cards are not'coincident), while the magnetic sensor is
turned off when verification is made, that is, when the key card 6' is coincident
with the set card 5'. In this embodiment of the magnetic card verifying device according
to the present invention, as will be mentioned later, the saturable transformer does
not need a secondary winding but requires only a primary winding so that the magnetic
sensor uses the saturable core.
[0022] Fig. 4 is a graph of the input to output characteristic of the saturable core of
the magnetic sensor used in the first embodiment of the magnetic card verifying device
according to the present invention to show its principle. In the graph of Fig. 4,
the references have the same meaning as in Fig. 2. Reference letter V' designates
a terminal voltage across the primary winding (see Fig. 5). First, in absolute value,
the saturation magnetic field Hs of the magnetic core is selected so that it is larger
than the magnitude of the magnetic field generated from each magnetic signal or key
code recorded on any card, including the set card 5'. In the graph of Fig. 4, when
the magnetic field generated by the magnetic signal or key code recorded on the set
card 5' is as shown by a letter A, the saturable core is not yet saturated and a large
terminal voltage V
1 is generated from the winding. When the magnetic field from the key code recorded
on the key card 6' is as shown by a letter B, this key card magnetic field B is added
to the set card magnetic field A so that the total magnetic field exceeds the saturation
magnetic field +Hs of the core. Thus, the saturable core is saturated, the terminal
voltage V' drops and accordingly, the magnetic sensor is turned off. In this state,
a verified output indicative of coincidence between the magnetic signals of the set
and key cards 5' and 6' is produced.
[0023] When the magnetic field generated from the key card magnetic signal is as shown by
B' in Fig. 4, the magnetic fields A and B' oppose one other. Thus, the saturable core
is not saturated, the terminal voltage V' does not drip but remains large and the
magnetic sensors remains in the on state. In this state, the verifying device does
not generate any output, verifying that the set card 5' and the key card 6' are not
coincident with each other.
[0024] When, on the contrary, as shown in Fig. 2, the set card magnetic field A is larger
than the saturation magnetic field +Hs of the saturable core, it is possible to verify
the coincidence among the ternary signal of the key card magnetic fields shown by
B, B' and B° (of no signal). However, when as shown in Fig. 4 the magnetic field A
generated by the set card 5' is smaller than the saturation magnetic field +Hs, the
magnetic field B° of no magnetic signal is meaningless so that verification is made
of the binary signal.
[0025] Therefore, when both of the set and key cards are verified to be coincident, the
terminal voltage V' of the winding becomes small, while when no verification is made
such as when the set and key cards are not coincident, the terminal voltage V' is
large. Thus, even if a disturbing voltage is applied to the verifying device, the
disturbing voltage causes the verifying device to indicate non- coincidence and hence
no misoperation is caused.
[0026] Fig. 5 is a connection diagram showing the above first embodiment of the verifying
device according to the invention on the basis of the above-mentioned principle, in
which a plurality of magnetic signals or key code points are verified. In Fig. 5,
like parts corresponding to those of Fig. 3 are marked with the same and similar references
and will not be described in detail for simplicity. In this case, only a primary winding
2' is wound around each saturable core 1', and the saturable core 1' and the primary
winding 2' constitute a saturable magnetic sensor S'. The high frequency oscillator
4 has a frequency of, for example, 500 kHz and an output voltage of 10 Vpp. The high
frequency oscillator 4 applies a voltage to each of a plurality of the windings 2'
through each of resistors r of, for example, 1 k. Each of the windings 2' is connected
at one end to the base and at its other end to the emitter of a respective transistor
Q serving as a switching element. The collectors of the respective transistors Q are
connected together and then connected through a resistor R of, for example, 10 k to
the positive (+) terminal of a power source. The emitters of the transistors Q are
also coupled together and then connected to the negative (-) terminal of the power
source. Between the terminals of the power source is connected a capacitor C of, for
example, 0.1 pF and a verified output terminal 9 is led out from the common connection
point of the collectors of the transistors Q.
[0027] With the above verifying device shown in Fig. 5, when the key card 6' (not shown)
is verified as coincident with the set card 5' (that is, when all the key codes 6
(not shown) of the key card are verified as being coincident with all the set codes
5 of the set card 5' by all the magnetic sensors S', respectively), and hence the
magnetic sensors S' are all turned off, all of the transistors Q are turned off so
that the verified output at the output terminal 9 becomes a high voltage, indicating
that the magnetic signals on the set and key cards 5' and 6' are coincident. Even
if only one pair of the magnetic signals 5 and 6 on the cards is not coincident, the
terminal voltage V' at the winding 2' of the corresponding sensor S' becomes high,
so that the corresponding transistor Q is turned on. Thus, the verified output becomes
a low voltage, indicating that the magnetic signals on the cards are not coincident.
[0028] The saturable core 1 is formed of an I-shape thin plate made of permalloy. In this
case, in order to increase the saturation magnetic field Hs' it is sufficient to increase
the number of such permalloy thin plates. Thus, the saturation magnetic field Hs'
can be increased with ease in accordance with the magnitude of the magnetic signal
recorded on the set and/or key card.
[0029] According to this first verifying device, even when the verifying device is applied
with the induction voltage and so on upon non-verification, the magnetic sensor S'
holds their on-state. Thus, in principle, this verifying device has the advantage
that it is resistant to disturbing voltages.
[0030] However, if a key card having a magnetic signal or key code recorded thereon which
generates a magnetic field considerably larger than the saturation magnetic field
Hs is loaded into the verifying device, it may be that, regardless of the direction
of the magnetic field generated by the key card, the magnetic sensor S' will be saturated
without use of the key code, and a verified output indicative of coincidence between
the set and key cards will be generated.
[0031] Now, a second embodiment of the magnetic card verifying device according to the present
invention which is free of the disadvantage of the first embodiment will be described.
[0032] Fig. 6 is a schematic diagram showing the second embodiment of the present invention,
and the illustrative example shows by way of example the case where the verifying
device is applied to verify a key card which includes 12 magnetic signal or key code
points to be verified. In this example, of the 12 magnetic signal points, 6 points
are verified by a prior art verifying device (PVD) connected in cascade as shown in
Fig. 3, while the remaining 6 points are verified by the first verifying device (IVD)
connected in parallel as shown in Fig. 5. The outputs from both the verifying devices
PVD and IVD are supplied through amplifiers 11P and 111 to two input terminals of,
for example, an AND circuit and the output from the AND circuit is fed to a coincidence
verified output terminal 12. Thus, a verifying device capable of verifying 12 magnetic
signal points, in which the prior art verifying device PVD is combined with the IVD,
is provided.
[0033] In this case, the verifying device PVD is provided such that the saturable transformers
S as, for example, shown in Fig. 3 are connected in cascade, while the verifying device
IVD is provided such that the magnetic sensor S' as, for example, shown in Fig. 5
are connected in parallel as set forth above. Since including the shape of the saturable
core, the winding and the circuit, various modifications can be considered for the
magnetic sensors, the above embodiment is mere example.
[0034] With the combination of the above two verifying devices PVD and IVD, the sensors
of the verifying section PVD generates a small output upon non-verification, but if
a disturbing voltage is applied thereto by electrostatic or electromagnet induction,
there is a possibility that the magnetic sensors of the prior art verifying section
PVD are instantly turned on to malfunction. On the other hand, the magnetic sensors
of the verifying section IVD are in on-state upon non-verification and generate a
large output under such state. Thus even when a disturbing voltage is applied to the
magnetic sensor S' of the verifying section IVD, the output from the magnetic sensor
S' never becomes small and the magnetic sensor S' is turned off. As a result, the
verifying device IVD does not generate an output indicative of coincidence between
the magnetic signals recorded on the set and key cards. Therefore, the verifying device
of the invention shown in Fig. 6 is resistant to the disturbing voltages.
[0035] Furthermore, if a magnetic or key card which generates a strong magnetic field is
intentionally used in the verifying section IVD, it may be that regardless of the
coincidence of the key code, the verifying section IVD will generate an output indicative
of coincidence. However, the verifying section PVD is free from this disadvantage
so that the whole of the verifying device shown in Fig. 6 does not produce an output
indicative of coincidence between the magnetic signals in such case. That is, the
verifying device according to the present invention shown in Fig. 6 is safe against
a powerful magnetic card.
[0036] As set forth above, since the second embodiment of the verifying device according
to the present invention utilizes a convenient combination of those devices shown
in Fig. 3 and Fig. 5, when the magnetic signals recorded on the set and key cards
are not coincident in either of the verifying sections PVD and IVD, the verifying
device does not produce an output respresenta- tive of coincidence therebetween. Thus,
the second verifying device according to the present invention can obviate the above
disadvantage of the first embodiment and the defects of the prior art and is very
safe.
[0037] While in Fig. 6, 6 magnetic signal points are assigned to the verifying sections
PVD and IVD, it is needless to say that if the combination of the assignment of the
magnetic signal points is arbitrarily changed so that 10 magnetic signal points are
assigned to the verifying section PVD and 2 magnetic signal points are to the verifying
section IVD, the same effect can be achieved.
1. A verifying device for a key card (6') on which a magnetic signal (6) is recorded
comprising:
a) a set card (5') on which a predetermined reference magnetic signal (5) is recorded;
b) a first magnetic sensor (S') consisting of a first saturable core (1') and a winding
(2') wound thereon;
c) an oscillator (4) for supplying a voltage to said winding (2');
d) a switching element (Q) connected to said winding (2');
e) a power source connected to said switching element (Q); and
f) an output terminal (9) connected to said switching element (Q), for connection
to an actuator,
characterized in that:
the saturation magnetic field (Hs') of said first saturable core (1') is larger in
absolute value than the magnetic field (A) generated by the reference magnetic signal
(5) recorded on said set card (5') and the magnetic field (B) generated by the key
card magnetic signal (5) when said key card (6') is a correct card, so that when a
correct key card (6') to be verified is inserted into the device with said set card
(5') the sum of the magnetic field (A + B) from said set card (5') and said key (6')
card is larger is absolute value than the saturation magnetic field (Hs') of said
first saturable core (1'), so that said saturable core (1') is saturated, no output
appears at said winding (2'), said switching element (Q) is turned off and an output
indicating that said key card (6') is coincident with said set card (5') is produced
at the output terminal (9).
2. A verifying device for a key card according to claim 1 further comprising:
g) a second magnetic sensor (S) consisting of a second saturable core (1) and primary
(2) and secondary (3) windings wound on said second saturable core (1), said primary
winding (2) being connected to said oscillator (4);
h) a second output terminal (8) connected to said secondary winding (3)
i) an AND circuit (AND) having input terminals connected to said first (9) and second
(8) output terminals; and
j) a third output terminal (12) led out from said AND circuit (AND),
the saturation magnetic field (Hs) of said second saturable core (1) being smaller
in absolute value than that generated by the reference signal (5) recorded on said
set card (5') so that said second saturable core (1) is saturated by the magnetic
field (A) from said set card (5') and hence no output is produced at said second output
terminal (8) when no key card is present but when a correct key card (6') is inserted
into said verifying device, said second saturable core (1) becomes unsaturated by
the magnetic field (B) from said correct key card (6') to thereby produce an output
at said second output terminal (8);
whereby when said key card (6') is verified as being coincident with said set card
(5') by said first (5') and second magnetic sensors and outputs are provided at the
first (9) and second (8) output terminals, respectively, said AND circuit (AND) delivers
an output to said third output terminal (12).
3. A verifying device for a key card according to claim 1 or claim 2, further comprising
a plurality of magnetic sensors (S') connected in parallel each of which is the same
as said first magnetic sensor (S').
4. A verifying device for a key card according to claim 2 or claim 3 when dependent
on claim 2 further comprising a plurality of magnetic sensors (S) connected in cascade,
each of which is the same as said second magnetic sensor (S).
1. Prüfvorrichtung für eine Schlüsselkarte (6'), auf der ein magnetisches Signal (6)
aufgezeichnet ist, mit
a) einer Einstellkarte (5'), auf der ein vorbestimmtes magnetisches Referenzsignal
(5) aufgezeichnet ist,
b) einem aus einem ersten sättigbaren Kern (1') und einer auf diesem aufgebrachten
Wicklung (2') bestehenden ersten magnetischen Sensor (S'),
c) einem Oszillator (4) zur Beaufschlagung der genannten Wicklung (2') mit einer Spannung,
d) einem mit der Wicklung (2') verbundenen Schaltelement (Q),
e) einer mit dem Schaltelement (Q) verbundenen Versorgungsquelle und
f) einem mit dem Schaltelement (Q) verbundenen Ausgangsanschluß (9) für die Verbindung
mit einem Betätigungsorgan,
dadurch gekennzeichnet,
daß magnetische Sättigungsfeld (Hs') des ersten sättigbaren Kerns (1') einen größeren
Absolutwert hat als das magnetische Feld (B), das von dem auf der Einstellkarte (5')
aufgezeichneten magnetischen Referenzsignal (5) und das von der S.chlüsselkarte erzeugt
wird, wenn diese Schlüsselkarte (6') eine korrekte Karte ist,
so daß dann, wenn eine zu prüfende korrekte Schlüsselkarte (6') zusammen mit der Einstellkarte
(5') in die Vorrichtung eingeführt wird, das magnetische Summenfeld (A + B) der Einstellkarte
(5') und der Schlüsselkarte (6') einen größeren Absolutwert hat als das magnetische
Sättigungsfeld (Hs') des ersten sättigbaren Kerns (1'), so daß
- dieser sättigbare Kern (1') gesättigt wird,
- an der genannten Wicklung (2') kein Ausgangssignal auftritt,
- das genannte Schaltelement (Q) ausgeschaltet wird und
- an dem Ausgangsanschluß (9) ein Ausgangssignal erzeugtwird, das anzeigt, daß die
Schlüsselkarte (6') mit der Einstellkarte (5') übereinstimmt.
2. Prüfvorrichtung für eine Schlüsselkarte nach Anspruch ferner mit
g) einem zweiten magnetischen Sensor (S), der aus einem zweiten sättigbaren Kern (1)
und auf diesem aufgebrachten Primär- und Sekundärwicklungen (2 bzw. 3) besteht, wobei
die Primärwicklung (2) mit dem Oszillator (4) verbunden ist,
h) einem zweiten Ausgangsanschluß (8), der mit der Sekundärwicklung (3) verbunden
ist,
i) einem UND-Glied (AND), dessen Eingänge mit dem ersten (9) und dem zweiten (8) Ausgangsanschluß
verbunden sind, und
j) einem dritten Ausgangsanschluß (12), der aus dem UND-Glied (AND) herausgeführt
ist,
wobei der Absolutwert des magnetischen Sättigungsfeldes (Hs) des zweiten sättigbaren
Kerns (1) kleiner ist als das von dem auf der Einstellkarte (5') aufgezeichneten Referenzsignal
(5) erzeugte Feld, so daß der zweite sättigbare Kern (1) von dem magnetischen Feld
(A) der Einstellkarte (5') gesättigt wird und deshalb an dem zweiten Ausgangsanschluß
(8) kein Ausgangssignal erzeugt wird, wenn keine Schlüsselkarte vorhanden ist, beim
Einbringen einer korrekten Schlüsselkarte (6') in die Prüfvorrichtung jedoch dersättigbare
Kern (1) durch das magnetische Feld der korrekten Schlüsselkarte (6') entsättigt und
an dem zweiten Ausgangsanschluß (8) ein Ausgangssignal erzeugt wird,
so daß dann, wenn durch den ersten (S') und den zweiten magnetischen Sensor Übereinstimmung
der Schlüsselkarte (6') mit der Einstellkarte (5') bestätigt wird und Ausgangssignale
an dem ersten (9) bzw. dem zweiten (8) Ausgangsanschluß erzeugt werden, das UND-Glied
(AND) ein Ausgangssignal an den dritten Ausgangsanschluß (12) liefert.
3. Prüfvorrichtung für eine Schlüsselkarte nach Anspruch 1 oder 2, ferner mit einer
Mehrzahl von zueinander parallel geschalteten magnetischen Sensoren (S'), die jeweils
in gleicher Weise ausgebildet sind wie der erste magnetische Sensor (S').
4. Prüfvorrichtung für eine Schlüsselkarte nach Anspruch 2 und, soweit dieser von
Anspruch 2 abhängt, nach Anspruch 3, ferner mit einer Mehrzahl von zueinander in Kaskade
geschalteten magnetischen Sensoren (S), die jeweils in gleicher Weise ausgebildet
sind wie der zweite magnetische Sensor (S).
1. Dispositif de vérification pour une carte servant de clé (6') sur laquelle un signal
magnétique (6) est enregistré, comprenant:
a) une carte de référence (5') sur laquelle un signal magnétique de référence prédéterminé
(5) est enregistré;
b) un premier détecteur magnétique (S') consistant en un premier noyau saturable (1')
et un enroulement (2') enroulé sur celui-ci;
c) un oscillateur (4) pour fournir une tension à l'enroulement (2');
d) un élément de commutation (Q) connecté à l'enroulement (2');
e) une source d'alimentation connectée à l'élément de commutation (Q); et
f) une borne de sortie (9) connectée à l'élément de commutation (Q) pour connexion
à un actionneur,
caractérisé en ce que:
le champ magnétique de saturation (Hs') du premier noyau saturable (1') est supérieur
en valeur absolue au champ magnétique (A) produit par le signal magnétique de référence
(5) enregistré sur la carte de référence (5') et au champ (B) produit par le signal
magnétique de carte servant de clé (5) quand ladite carte servant de clé (6') est
une carte correcte, de sorte que quand une carte servant de clé correcte (6') à vérifier
est insérée dans le dispositif avec laditezarte de référence (5'), la somme du champ
magnétique (A + B) en provenance de la carte de référence (5') et de la carte servant
de clé (6') est supérieure en valeur absolue au champ magnétique à la saturation (Hs')
du premier noyau saturable (1'), de sorte que le noyau saturable (1') est saturé,
qu'aucune sortie n'apparaît au niveau dudit enroulement (2'), que l'élément de commutation
(Q) est coupé et qu'une sortie indiquant que la carte servant de clé (6') coïncide
avec la carte de référence (5') est produite au niveau de la borne de sortie (9).
2. Dispositif de vérification d'une carte servant de clé selon la revendication 1,
comprenant en outre:
g) un second détecteur magnétique (S) comprenant un second noyau saturable (1) et
des enroulements primaire (2) et secondaire (3) bobinés sur le second noyau saturable
(1), le premier noyau saturable (2) étant connecté à l'oscillateur (4);
h) une seconde borne de sortie (8) connectée à l'enroulement secondaire (3),
i) un circuit ET (ET) ayant des bornes d'entrée connectées à la première (9) et à
la seconde (8) borne de sortie; et
j) une troisième borne de sortie (12) en provenance du circuit ET (ET),
le champ magnétique à la saturation (Hs) du second noyau saturable (1) étant inférieur
en valeur absolue à celui produit par le signal de référence (5) enregistré sur la
carte de référence (5') de sorte que le second noyau saturable (1) est saturé par
le champ magnétique (A) en provenance de la carte de référence (5') et qu'ainsi aucune
sortie n'est produite sur la seconde borne de sortie (8) quand aucune carte servant
de clé n'est présente, mais que, quand une carte servant de clé correcte (6') est
insérée dans le dispositif de vérification, le second noyau saturable (1) devient
non saturé par le champ magnétique (B) en provenance de la carte servant de clé correcte
(6') pour produire ainsi une sortie sur la seconde borne de sortie (8);
d'où il résulte que, quand la carte servant de clé (6') est vérifiée comme coïncidant
à la carte de référence (5') par les premier (S') et second détecteurs magnétiques,
et que des sorties sont fournies aux première (9) et seconde (8) bornes de sortie,
respectivement, le circuit ET (ET) fournit une sortie à la troisième borne de sortie
(12).
3. Dispositif de vérification d'une carte servant de clé selon la revendication 1
ou la revendication 2, comprenant en outre une pluralité de détecteurs magnétiques
(S') connectés en parallèle dont chacun est identique au premier détecteur magnétique
(S').
4. Dispositif de vérification d'une carte servant de clé selon la revendication 2
ou la revendication 3 prise dans sa dépendance d'avec la revendication 2, comprenant
en outre une pluralité de détecteurs magnétiques (S) connectés en cascade dont chacun
est identique au second détecteur magnétique (S).